The genetically modified salmon has been approved for human consumption, and that makes it interesting for salmon farms - and potentially dangerous for wild salmon.

Whether the genetically modified salmon are a hazard for humans is not certain, and actually quite unlikely, but there is no doubt that's it's a very severe potential threat to the wild salmon.

The US Food and Drug Administration (FDA) has approved the modified fish on the two main issues that have been up for debate: human and environmental impact. It declares that AquaBounty Technologies - the company behind the gene modified fish - has sufficient safety measures, ensuring that the fish have no significant environmental impact and that they are safe for human consumption.
While the latter is fairly sure, at least if you don't count bacterial infections such as listeria known from caged salmon and rainbow trout, the assessment that the fish are without environmental impact does indeed leave some doubt.

The plan is to engineer the eggs in secure tanks in Canada, and then ship the fish to Panama to mature. All the fish are female and triploids, containing three copies of each chromosome rather than two, rendering them sterile. Triploids are known to grow faster and bigger, but even so, the fish are also genetically modified with a Chinook gene that makes them eat more (five times the normal rate) and grow even faster (twice the normal rate).

According to the Organic Consumers Association (OCA) it's estimated that 95 percent of the modified salmon are sterile, but the remaining 5 percent may be fertile. FDA says the probability of the tank reared salmon escaping into the wild is extremely remote, but has given little evidence to support that assumption.
The modified fish eat five times more food than wild salmon - that's what they are modified to do - and on top of that they have less fear of predators. Just a few escapees, and the wild salmon population would be at risk, and the facilities for growing the fish to marketable size have been known to fail, as this report from Outside magazine covers.

So, like it's been the case with caged salmon, we have yet another threat on the way for the wild salmon.